Purification of water



Patented Aug. 2, 1932 Ldtttdd OSCAR ADLEB AND RUDOIZF ADLER, OF KARLSBAD, GZECI-IOSLOVAKIA PURIFICATION OF WATER No Drawing. Original application filed July .9, 1926, Serial No. 121,491, ai1a in Czechoslovakia July 15, 1925. Divided and this application filed July 13,- 1929,'Seria1 No. 378,172.

This invention relates to a process of purifying Water, by which it is freed from germs and which, at the same time, results in pure water containing no free or active chlorine.

5 This application is a division of our copending application Serial No. 121, l91, filed July 9, 1926, Patent No. 1,771,518, dated July 29, 1930.

It has heretofore been proposed to remove the excess of free or active chlorine, remaining in the water, by the use, of carbonaceous -1natter, or by active carbon, which chemically combines or fixes the chlorine, or adsorbs the same. But such processes present the oblfi'jection that the carbonaceous material in the mass, as it chemically combines or adsorbs the chlorine, gradually loses its activity to do so and finally becomes entirely inert, On

, account of the possibility of free or active chlorine being, therefore, present in the purifled water, it is necessary to constantly test the same for free chlorine. As soon as the capac-' ity of the carbon or carbonaceous material to adsorb or combine the chlorine is exhausted, it must be replaced by fresh material or be revivified. In carrying out such processes, the added free or active chlorine must absolutely not be present in the pure water. Ac-- carbon does not, in fact, possess a chemical afiinity for chlorine, as is well known. By

elementary carbon is understood such carbone as lamp black, bone carbon, etc., which, as Chemists Well know, do not have the capacity of forming chemical chlorine compounds with chlorine dissolved in water.

In contradistinction to the prevalent scientific opinion, according to which elementary carbon is resistant at normal temperatures to dilute watery solutions of free or active chlorine, we have found that elementary carbon, after saturation with free chlorine in watery solution and in the case where the quan tity of carbon used is large relatively to the amount of chlorine flowing over the surface of the carbon in a unit time, is subjected to a chemical reaction, which can be expressed by the following equations: i

' C +2H O +4CI=4HG1+ CO2 C 2NaOCl= EZNaOl CO,

Stated in words, this means that the total amount of free or active chlorine, in passing through the carbon, is converted into the chlorine ions, without-the carbon becoming saturated and, therefore, Without the necessity of renewing or reactivating'the carbon.

In the present process, therefore, in contradistinction to prior processes, the total amount of free or active chlorine used, after passing through the carbon, appears continuously as chlorine ions in the purified water. V v

The quantity of carbon. required in the above described operation for the continuous and quantitative conversion into the chlorine ions, is dependent upon the kind used, and especially upon its surface area, and must be determined by experiment in eachf case. The numerous materials consisting of, or, in part, of carbon and found in commerce, such as hardcoal, brown coal or the cokes made therefrom, are used for the most part, while soot, wood carbon, bone carbon, etc. and particularly the activated carbon, distinguished byits large surface area formation, are used to a less degree, I

As disinfecting media,free chlorine in gaseous state or in'watery solution, hypochlorite, chloride of lime, or other substances giving off free vor active chlorine can be used inthe usualway. H l Y v According to the present invention, therefore, the water .to-be freed from germs is first mixed with a quantity of free or active chlorine amply sufficient to surely kill all 9 the germs, and then after a suitable time, is conducted. over a sufficient-quantity of any desired kind of carbon, the surface area of which is sufficiently great, after becoming saturated with chlorine, to convert the remaining excess of free or activechlorine quantitatively into the chlorine ions. The small amounts of carbon, used up in the said chemical process, must obviously be replaced fromtime to time.

bodies.

1 a complete standstill.

Since in commerce difierent kinds of carbon, as for example, soot, active carbon and the like, are often obtainable in powder form, which presents a great resistance to the passage of water in large quantities and, there- I of from 800'1500, under exclusion of oxygen, or mixing the powdered carbonaceous material with a watery solution of an alkali silicate, preferably with the addition. of a substance containing silicic acid, such as quartz, clay, feldspar etc, into a thick paste and then, after suitably shaping it in the moist state, subjecting the pieces to a rapid heating at a moderate temperature.

It has alsobeen discovered that a'considerably enhanced disinfecting action also occurs when the water, after the addition of a definite quantity of free chlorine, a hypochlorite or chloride of lime, and before passing through the materials consisting of carbon of the kind described, is conducted through porous bodies refractory as regards the chlorine products mentioned and formed from pulverulent, granular or from any desired shaped substances which reduce or prevent completely the movement of the organisms present in the water, relatively tothe velocity of flow of the water flowing through the porous bodies. Care must, however, be taken that the water still contains suflicient free chlorine, hypochlorite or chloride of lime, both during the passage through the porous bodies and also on leaving the same, so as to kill organisms present in the water or accumulating inside the porous Many materials which are refractory toward chlorine or the chlorine compounds mentioned such as clay, sand, asbestos, kieselguhr, glass-wool, and the like in pulverulent or granular form or shaped according to-known methods as pieces, plates,

tubes closed at one end, and the like, may be employed as the porous bodies.

In those cases in which the water being freed from organisms contains coarse suspended particles, the perviousness of theporous bodies might be decreased by the retention of these particles on or in the porous body so that the operation of'the plant would. be impaired or the flow of water bronghtto To guard against this possible undesirable contingency, it has provedpreferable to pass water in the direction opposite to that. of the normal flow from time to time. and as occasion demands, chlorine, hypochlorite or chloride of. lime being added immediately at the commencement or preferably toward the end of this back flushing in quantities sufficient to destroy any organisms still possibly remaining in the porous body.

As mentioned, the water now leaving the porous bodies, free from organisms but still containing considerable chlorine, hypochlo rite or chloride of lime, is passed over materials consisting substantially of carbon of the kind described, whereby in consequence of the described conversion of the chlorine,

hypochlorite or chloride of lime the water is quantitatively freed from these. Since, however, the possibility that bacteria might on occasion escape destruction and be re tained by the carbon-containing material is not excluded, it has been found preferable to sterilize these carbon-containing mate rials from time to time and as occasion demands, by means of steam, hot air or hot water so as to kill any organisms which might be situated therein.

We claim as our invention A method of freeing water from organisms, which compriscs the steps of mixing the water with a substance containing chlo rine; passing the water through porous refractory substances which prevent the movement of the organisms situated in the water; then conducting the water over a material containing carbon to convert the chlorine substance into a chlorine compound; and flushing out any solid particles accumulated in the porous bodies by a stream of water treated with a substance containing chlorine in a. direction opposite to that of the normal flow of water to kill the organisms present in the porous bodies.

In testimony whereof we affix our signatures.

OSCAR ADLER. 'RUDOLF A'DLER. 

